Click rates and silences of sperm whales at Kaikoura, New Zealand

2005 ◽  
Vol 118 (1) ◽  
pp. 523-529 ◽  
Author(s):  
Lesley A. Douglas ◽  
Stephen M. Dawson ◽  
Nathalie Jaquet
Keyword(s):  
New Zealand ◽  
Sperm Whales

scholarly journals Correcting Positional Errors in Shore-Based Theodolite Measurements of Animals at Sea

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Ophélie Sagnol ◽  
Femke Reitsma ◽  
Christoph Richter ◽  
Laurence H. Field
Keyword(s):  
New Zealand ◽  
Habitat Use ◽  
Marine Mammal ◽  
Positional Information ◽  
Physeter Macrocephalus ◽  
Sperm Whales ◽  
Vertical Angle ◽  
Position Accuracy ◽  
Wide Range ◽  
The Difference

Determining the position of animals at sea can be particularly difficult and yet, accurate range and position of animals at sea are essential to answer a wide range of biological questions. Shore-based theodolite techniques have been used in a number of studies to examine marine mammal movement patterns and habitat use, offering reliable position measurements. In this study we explored the accuracy of theodolite measurements by comparing positional information of the same objects using two independent techniques: a shore-based theodolite station and an onboard GPS over a range of 25 km from the shore-based station. The technique was developed to study the habitat use of sperm whales (Physeter macrocephalus) off Kaikoura, New Zealand. We observed that the position accuracy fell rapidly with an increase in range from the shore-based station. Results showed that the horizontal angle was accurately determined, but this was not the case for the vertical angle. We calibrated the position of objects at sea with a regression-based correction to fit the difference in distance between simultaneously recorded theodolite fixes and GPS positions. This approach revealed the necessity to calibrate theodolite measurements with objects at sea of known position.

IMPACTS OF COMMERCIAL WHALE WATCHING ON MALE SPERM WHALES AT KAIKOURA, NEW ZEALAND

2006 ◽  
Vol 22 (1) ◽  
pp. 46-63 ◽  
Author(s):  
Christoph Richter ◽  
Steve Dawson ◽  
Elisabeth Slooten
Keyword(s):  
New Zealand ◽  
Sperm Whales ◽  
Whale Watching ◽  
Male Sperm

Seasonal distribution and diving behaviour of male sperm whales off Kaikoura: foraging implications

2000 ◽  
Vol 78 (3) ◽  
pp. 407-419 ◽  
Author(s):  
Nathalie Jaquet ◽  
Stephen Dawson ◽  
Elisabeth Slooten
Keyword(s):  
New Zealand ◽  
Food Supply ◽  
Seasonal Distribution ◽  
Diving Behaviour ◽  
Physeter Macrocephalus ◽  
Sperm Whales ◽  
Non Invasive ◽  
Male Sperm ◽  
Adequate Food ◽  
Whaling Industry

Male sperm whales (Physeter macrocephalus) were the preferred target of the whaling industry between 1950 and 1985, but despite hundreds of thousands of kills, very little is known about their ecology. To partially redress this, we present data on residency, seasonal distribution, and diving behaviour of individually identified sperm whales off Kaikoura, South Island, New Zealand, gathered during 15 field seasons over 8 years. One hundred and thirty-six sperm whales were identified within the study area. A lack of statistically significant differences in the abundance of sperm whales between summer and winter, and among the 15 seasons of fieldwork, suggests an adequate food supply year-round. Significant differences in distribution between summer and winter suggest that off Kaikoura, male sperm whales may change their diet in response to fluctuations in prey biomass. Diving behaviour was also significantly different between summer and winter: sperm whales dived for longer, stayed longer at the surface, and travelled farther between consecutive fluke-ups in summer than in winter. Unlike female sperm whales, males at Kaikoura spent little time at the surface; they spent about 83% of their total time under water. This paper represent the most extensive non-invasive study of male sperm whales and provides new insights into their ecology.

Sign in / Sign up

Export Citation Format

Share Document